The base subnet therefore is the lowest binary value that can be written without changing the output of an AND operation of the subnet mask and IP…

1111 1000 AND

0010 1010 equals

0010 1000 – which is .40

/24 is standard class C mask.

Adding the 5 bits from the .248 mask gives /29

Question No: 83 – (Topic 3)

Refer to the exhibit.

PC1 pings PC2. What three things will CORE router do with the data that is received from PC1? (Choose three.)

The data frames will be forwarded out interface FastEthernet0/1 of CORE router.

The data frames will be forwarded out interface FastEthernet1/0 of CORE router.

CORE router will replace the destination IP address of the packets with the IP address of PC2.

CORE router will replace the MAC address of PC2 in the destination MAC address of the frames.

CORE router will put the IP address of the forwarding FastEthernet interface in the place of the source IP address in the packets.

CORE router will put the MAC address of the forwarding FastEthernet interface in the place of the source MAC address.

Answer: B,D,F Explanation:

The router will forward the frames out the interface toward the destination – B is correct. Since the router will has the end station already in it’s MAC table as see by the “show arp” command, it will replace the destination MAC address to that of PC2 – D is correct.

The router will then replace the source IP address to 172.16.40.1 – E is correct.

Question No: 84 – (Topic 3)

An administrator must assign static IP addresses to the servers in a network. For network 192.168.20.24/29, the router is assigned the first usable host address while the sales server is given the last usable host address.

Which of the following should be entered into the IP properties box for the sales server?

Therefore the first usable IP address is 192.168.20.25 (assigned to the router) and the last usable IP address is 192.168.20.30 (assigned to the sales server). The IP address of the router is also the default gateway of the sales server.

Question No: 87 – (Topic 3)

The router at 208.149.23.130 is a secondary DR in case the primary fails.

Two router IDs have the same OSPF priority and are therefore tied for DR election

The DR election is still underway and there are two contenders for the role.

Answer: A Explanation:

OSPF elects one DR per multi-access network. In the exhibit there are two DR so there must have more than one multi-access network.

Question No: 88 – (Topic 3)

Which three approaches can be used while migrating from an IPv4 addressing scheme to an IPv6 scheme? (Choose three)

static mapping of IPv4 address to IPv6 addresses

configuring IPv4 tunnels between IPv6 islands

use DHCPv6 to map IPv4 addresses to IPv6 addresses

use proxying and translation (NAT-PT) to translate IPv6 packets into IPv4 packets

configure IPv6 directly

enable dual-stack routing

Answer: B,D,F Explanation:

Connecting IPv6 islands with tunnels

An IPv6 island is a network made of IPv6 links directly connected by IPv6 routers. In the early days of IPv6 deployment, there are many IPv6 islands. IPv6 in IPv4 tunnels are used to connect those islands together. In each island, one (or more) dual stack routers are

designated to encapsulate and decapsulate IPv6 packets within IPv4 packets. Different mechanisms have been developed to manage tunnels: automatic tunnels3, configured tunnels3, tunnel brokers3, 6over43, 6to43,…

The NAT-PT method enables the ability to either statically or dynamically configure a translation of a IPv4 network address into an IPv6 network address and vice versa. For those familiar with more typically NAT implementations, the operation is very similar but includes a protocol translation function. NAT-PT also ties in an Application Layer Gateway (ALG) functionality that converts Domain Name System (DNS) mappings between protocols.

Dual Stack

The simplest approach when transitioning to IPv6 is to run IPv6 on all of the devices that are currently running IPv4. If this is something that is possible within the organizational network, it is very easy to implement.

However, for many organizations, IPv6 is not supported on all of the IPv4 devices; in these situations other methods must be considered.

Question No: 89 – (Topic 3)

OSPF routing uses the concept of areas. What are the characteristics of OSPF areas? (Choose Three.)

Each OSPF area requires a loopback interface to be configured.

Areas may be assigned any number from 0 to 65535.

Area 0 is called the backbone area.

Hierarchical OSPF networks do not require multiple areas.

Multiple OSPF areas must connect to area 0.

Single area OSPF networks must be configured in area 1.

Answer: B,C,E Explanation:

Definition of OSPF areas: An OSPF network may be structured, or subdivided, into routing areas to simplify administration and optimize traffic and resource utilization. Areas are identified by 32-bit numbers, expressed either simply in decimal, or often in octet-based dot-decimal notation, familiar from IPv4 address notation.